Frisian

The Frisian languages are a closely related group of Germanic languages, spoken by about 500,000 members of Frisian ethnic groups, who live on the southern fringes of the North Sea in the Netherlands and Germany. The Frisian languages are the second closest living languages to English, after Scots. However, modern English and Frisian are mostly unintelligible to each other. Frisian languages bear similarities to Low German, Dutch (from which many Frisian words have been borrowed), and Danish. Additional shared linguistic characteristics between the Great Yarmouth area, Friesland, and Denmark are likely to have resulted from the close trading relationship these areas maintained during the centuries-long Hanseatic League of the Late Middle Ages. Wikipedia